Radio speaker diaphragm



D69 10, l929- F. E. GREswoLD I RADIO SPEAKER DIAPHRAGM Filed 001:. 27. 1925 ATTORNEY;

- Patented Dec. 10, 1929 UNITED sfrA'l'Es PATENT OFFICE FORREST GRESWOLD, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO ATWATER KENT MANUFACTURING COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A COR- roRArIoN or PENNSYLVANIA RADIO SPEAKER. DIAPHRAGM Application led October 27, 1925. Serial'No. 65,076.

My invention relates to diaphragms of telephonie apparatus, and more particulary to conical diaphragms of large diameter for' amplifying telephones, loud speakers or radio speakers utilized in connection with radio receiving systems.

In accordance with my invention, the diaphragm, of paper, or similar material easily deformed or injured, particularly at its outer end or periphery, has its periphery orouter end free and unconiined, and has applied thereat a stiffening or strengthening member, preferably embracing the edge of the diaphragm, and serving as a protective structure, of cloth, felt, or equivalent material.

Further in accordance with my invention, there is provided a further guard or protective element, of rigid material, as metal, substantially spaced from the diaphragm and from the protective structure directly applied to the diaphragm adjacent its outer ed e.

l/Iy invention resides in diaphragm structure of the character yhereinafter described and claimed. y

For an illustration of one of the forms my invention may take, reference ,is toL be had to the accompanying drawing, in which:

Fig. 1 is a vertical sectional view, partly in elevation, of structure embodying my invention. x

Fig. 2 is a fragmentary sectional view, partly in elevation, on enlarged scale.

Referring to the drawing, 1 is a base to which is secured one of the arms 3 of a structure for supporting the magnet system, diaphragm and guard structure therefor. Carried by the arms 3 is the member 4, uponl whichri's secured the magnet system comprising the permanent magnet field frame or yoke 5, pole piece structure 6, magnet wind-I ing 7, and vibratile armature bar ormember 8 secured at its one end to the yoke 5 and having its free end operatively relatcdito the pole piece structure Secured to the vibratile armature member 8 is the pin or rod 9 constituting the sole support for the diaphragm and serving to vibrate it. The vconical diaphragm 10, of paper, sheet metal or equivalent material, is

of relatively large diameter, as upwards of six inches, and has secured thereto at its apex or center sheetmetal conical structure 11, to which is secured the member 12 by which the diaphragm is secured to the pin 9 by set screw 13.

The arms 3 carry the annular shield or guard member 14, which surrounds but is spaced from the outer end or periphery of the diaphragm 10, allowing it to vibrate freely throughout without restraint by or contact with the guard structure 14.

Applied to the diaphragm 10 at its pe-l vat or adjacent its periphery in event the guard structurel4 be'bent or deformed to position closely 'adjacent to or in contact with the diaphragm. And when the guard structure 14 is not utilized, the member 15 nevertheless serves to strengthen and protect the' diaphragm adjacent its periphery against4A distortion, deformation or breakageleaving the diaphragm to vibrate freely and unrestrainedly at its outer periphery, the material y15 being sufficiently light or small in mass orI quantity as not to materially impede or dampen the diaphragm'vibrations.

The'diaphragm is free of restraint at its periphery, and is supported solely at its apex or center, and there the vibrations of the vibratile armature member 8 are imparted to it.

As 'ndicated,the guard member 14 is substantflally spaced from the diaphragm 10 itself, and in addition, from the protective 'member 15, which tooin vibration is unrestrained and does not come into contact with the guard 14, which latter, as indicated, preferably extends around or embraces the periphery or outer edge of the diaphragm 10 and the member 15, and throughout is substantially spaced from both.

What I claim is:

1. A sound-reproducing diaphragm of the free edge type having attached thereto at its periphery a protecting element.

2. A conical diaphragm of large diameter having a freely vibrating periphery and a protectingv element of fibrous material attached to said periphery.

3. A conical diaphragm of large diameter having a freely vibrating periphery, and a protectingelement of fabric attached to said periphery.

4. A sound-reproducing diaphragm of the free edge type having attached thereto at its periphery a protecting element extending circumferentially of said periphery.

5. A sound-reproduclng diaphragm of the free edge type having attached thereto at its periphery a protecting element on each side thereof.

6. A conical diaphragm of large diameter having a freely vibrating periphery, and a protecting element attached to said periphery on each side thereof and continuous across the edge thereof.

y vibratable periphery, a protecting element attached to said periphery, and a guard 'member embracing the periphery of the diaphragm and said protecting element and substantially spaced therefrom.

10. A sound-reproducing diaphragm of the free edge type, and an circumferential element attached thereto at the peri-phery of Said f'aphragm having a width small as com- .pared to the distance tothe center of the diaphragm. y

11. A conical diaphragm of the free edge type, and an element attached thereto at the periphery of said diaphragm having a Width small as compared to the distance to the vertex of the cone.

12. In combination, a sound-reproducing diap-hragm of the free edge type, a protecting element attached to the periphery of said diaphragm, and a guard element surrounding said periphery and substantially spacedfrom said protecting element.

13. In combination, a sound-reproducing ldiaphragm of the free edge type, a protectingelement attached to the periphery of said dia- FORREST E. GRESWOLD. 

